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63 lines
1.8 KiB
OCaml
63 lines
1.8 KiB
OCaml
(* [[file:~/QCaml/particles/electrons.org::*Type][Type:2]] *)
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type t = {
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n_alfa : int ;
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n_beta : int ;
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}
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(* Type:2 ends here *)
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(* | ~make~ | ~make n_alfa n_beta~ |
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* | ~of_atoms~ | Creates the data relative to electrons for a molecular system described by ~Nuclei.t~ for a given total charge and spin multiplicity. | *)
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(* [[file:~/QCaml/particles/electrons.org::*Creation][Creation:2]] *)
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open Common
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let make n_alfa n_beta =
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{ n_alfa ; n_beta }
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let of_atoms ?multiplicity:(multiplicity=1) ?charge:(charge=0) nuclei =
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let positive_charges =
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Array.fold_left (fun accu (e, _) -> accu + Charge.to_int (Element.to_charge e) )
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0 nuclei
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in
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let negative_charges = charge - positive_charges in
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let n_elec = - negative_charges in
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let n_beta = ((n_elec - multiplicity)+1)/2 in
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let n_alfa = n_elec - n_beta in
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let result = { n_alfa ; n_beta } in
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if multiplicity <> (n_alfa - n_beta)+1 then
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invalid_arg (__FILE__^": make");
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result
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(* Creation:2 ends here *)
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(* | ~charge~ | Sum of the charges of the electrons |
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* | ~n_elec~ | Number of electrons |
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* | ~n_alfa~ | Number of alpha electrons |
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* | ~n_beta~ | Number of beta electrons |
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* | ~multiplicity~ | Spin multiplicity: $2S+1$ | *)
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(* [[file:~/QCaml/particles/electrons.org::*Access][Access:2]] *)
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let charge e =
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- (e.n_alfa + e.n_beta)
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|> Charge.of_int
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let n_alfa t = t.n_alfa
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let n_beta t = t.n_beta
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let n_elec t = t.n_alfa + t.n_beta
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let multiplicity t = t.n_alfa - t.n_beta + 1
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(* Access:2 ends here *)
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(* [[file:~/QCaml/particles/electrons.org::*Printers][Printers:2]] *)
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let pp ppf t =
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Format.fprintf ppf "@[n_alfa=%d, n_beta=%d@]" t.n_alfa t.n_beta
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(* Printers:2 ends here *)
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